scsi_scan.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,352 行 · 第 1/3 页

	 * 32, the lookup of the device flags (above) could be invalid,
	 * and it would be possible to take an incorrect action - we do
	 * not want to hang because of a short INQUIRY. On the flip side,
	 * if the device is spun down or becoming ready (and so it gives a
	 * short INQUIRY), an abort here prevents any further use of the
	 * device, including spin up.
	 *
	 * Related to the above issue:
	 *
	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
	 * and if not ready, sent a START_STOP to start (maybe spin up) and
	 * then send the INQUIRY again, since the INQUIRY can change after
	 * a device is initialized.
	 *
	 * Ideally, start a device if explicitly asked to do so.  This
	 * assumes that a device is spun up on power on, spun down on
	 * request, and then spun up on request.
	 */

	/*
	 * The scanning code needs to know the scsi_level, even if no
	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
	 * non-zero LUNs can be scanned.
	 */
	sdev->scsi_level = inq_result[2] & 0x07;
	if (sdev->scsi_level >= 2 ||
	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
		sdev->scsi_level++;

	return;
}

/**
 * scsi_add_lun - allocate and fully initialze a Scsi_Device
 * @sdevscan:	holds information to be stored in the new Scsi_Device
 * @sdevnew:	store the address of the newly allocated Scsi_Device
 * @inq_result:	holds the result of a previous INQUIRY to the LUN
 * @bflags:	black/white list flag
 *
 * Description:
 *     Allocate and initialize a Scsi_Device matching sdevscan. Optionally
 *     set fields based on values in *@bflags. If @sdevnew is not
 *     NULL, store the address of the new Scsi_Device in *@sdevnew (needed
 *     when scanning a particular LUN).
 *
 * Return:
 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
 *     SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
 **/
static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
{
	struct scsi_device *sdev_sibling;
	struct scsi_target *starget;
	unsigned long flags;

	/*
	 * XXX do not save the inquiry, since it can change underneath us,
	 * save just vendor/model/rev.
	 *
	 * Rather than save it and have an ioctl that retrieves the saved
	 * value, have an ioctl that executes the same INQUIRY code used
	 * in scsi_probe_lun, let user level programs doing INQUIRY
	 * scanning run at their own risk, or supply a user level program
	 * that can correctly scan.
	 */
	sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
	if (sdev->inquiry == NULL) {
		return SCSI_SCAN_NO_RESPONSE;
	}

	memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
	sdev->vendor = (char *) (sdev->inquiry + 8);
	sdev->model = (char *) (sdev->inquiry + 16);
	sdev->rev = (char *) (sdev->inquiry + 32);

	if (*bflags & BLIST_ISROM) {
		/*
		 * It would be better to modify sdev->type, and set
		 * sdev->removable, but then the print_inquiry() output
		 * would not show TYPE_ROM; if print_inquiry() is removed
		 * the issue goes away.
		 */
		inq_result[0] = TYPE_ROM;
		inq_result[1] |= 0x80;	/* removable */
	}

	switch (sdev->type = (inq_result[0] & 0x1f)) {
	case TYPE_TAPE:
	case TYPE_DISK:
	case TYPE_PRINTER:
	case TYPE_MOD:
	case TYPE_PROCESSOR:
	case TYPE_SCANNER:
	case TYPE_MEDIUM_CHANGER:
	case TYPE_ENCLOSURE:
	case TYPE_COMM:
		sdev->writeable = 1;
		break;
	case TYPE_WORM:
	case TYPE_ROM:
		sdev->writeable = 0;
		break;
	default:
		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
	}

	print_inquiry(inq_result);

	/*
	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
	 * spec says: The device server is capable of supporting the
	 * specified peripheral device type on this logical unit. However,
	 * the physical device is not currently connected to this logical
	 * unit.
	 *
	 * The above is vague, as it implies that we could treat 001 and
	 * 011 the same. Stay compatible with previous code, and create a
	 * Scsi_Device for a PQ of 1
	 *
	 * Don't set the device offline here; rather let the upper
	 * level drivers eval the PQ to decide whether they should
	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
	 */ 

	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
	sdev->removable = (0x80 & inq_result[1]) >> 7;
	sdev->lockable = sdev->removable;
	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);

	if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
		inq_result[56] & 0x04))
		sdev->ppr = 1;
	if (inq_result[7] & 0x60)
		sdev->wdtr = 1;
	if (inq_result[7] & 0x10)
		sdev->sdtr = 1;

	sprintf(sdev->devfs_name, "scsi/host%d/bus%d/target%d/lun%d",
				sdev->host->host_no, sdev->channel,
				sdev->id, sdev->lun);

	/*
	 * End driverfs/devfs code.
	 */

	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
	    !(*bflags & BLIST_NOTQ))
		sdev->tagged_supported = 1;
	/*
	 * Some devices (Texel CD ROM drives) have handshaking problems
	 * when used with the Seagate controllers. borken is initialized
	 * to 1, and then set it to 0 here.
	 */
	if ((*bflags & BLIST_BORKEN) == 0)
		sdev->borken = 0;

	/*
	 * Some devices may not want to have a start command automatically
	 * issued when a device is added.
	 */
	if (*bflags & BLIST_NOSTARTONADD)
		sdev->no_start_on_add = 1;

	/*
	 * If we need to allow I/O to only one of the luns attached to
	 * this target id at a time set single_lun, and allocate or modify
	 * sdev_target.
	 */
	if (*bflags & BLIST_SINGLELUN) {
		sdev->single_lun = 1;
		spin_lock_irqsave(sdev->host->host_lock, flags);
		starget = NULL;
		/*
		 * Search for an existing target for this sdev.
		 */
		list_for_each_entry(sdev_sibling, &sdev->same_target_siblings,
				    same_target_siblings) {
			if (sdev_sibling->sdev_target != NULL) {
				starget = sdev_sibling->sdev_target;
				break;
			}
		}
		if (!starget) {
			starget = kmalloc(sizeof(*starget), GFP_ATOMIC);
			if (!starget) {
				printk(ALLOC_FAILURE_MSG, __FUNCTION__);
				spin_unlock_irqrestore(sdev->host->host_lock,
						       flags);
				return SCSI_SCAN_NO_RESPONSE;
			}
			starget->starget_refcnt = 0;
			starget->starget_sdev_user = NULL;
		}
		starget->starget_refcnt++;
		sdev->sdev_target = starget;
		spin_unlock_irqrestore(sdev->host->host_lock, flags);
	}

	sdev->use_10_for_rw = 1;

	if (*bflags & BLIST_MS_SKIP_PAGE_08)
		sdev->skip_ms_page_8 = 1;

	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
		sdev->skip_ms_page_3f = 1;

	if (*bflags & BLIST_USE_10_BYTE_MS)
		sdev->use_10_for_ms = 1;

	/* set the device running here so that slave configure
	 * may do I/O */
	scsi_device_set_state(sdev, SDEV_RUNNING);

	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
		sdev->use_192_bytes_for_3f = 1;

	if (*bflags & BLIST_NOT_LOCKABLE)
		sdev->lockable = 0;

	if(sdev->host->hostt->slave_configure)
		sdev->host->hostt->slave_configure(sdev);

	/*
	 * Ok, the device is now all set up, we can
	 * register it and tell the rest of the kernel
	 * about it.
	 */
	scsi_sysfs_add_sdev(sdev);

	return SCSI_SCAN_LUN_PRESENT;
}

/**
 * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
 * @sdevscan:	probe the LUN corresponding to this Scsi_Device
 * @sdevnew:	store the value of any new Scsi_Device allocated
 * @bflagsp:	store bflags here if not NULL
 *
 * Description:
 *     Call scsi_probe_lun, if a LUN with an attached device is found,
 *     allocate and set it up by calling scsi_add_lun.
 *
 * Return:
 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
 *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
 *         attached at the LUN
 *     SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
 **/
static int scsi_probe_and_add_lun(struct Scsi_Host *host,
		uint channel, uint id, uint lun, int *bflagsp,
		struct scsi_device **sdevp, int rescan, void *hostdata)
{
	struct scsi_device *sdev;
	struct scsi_request *sreq;
	unsigned char *result;
	int bflags, res = SCSI_SCAN_NO_RESPONSE;

	/*
	 * The rescan flag is used as an optimization, the first scan of a
	 * host adapter calls into here with rescan == 0.
	 */
	if (rescan) {
		sdev = scsi_device_lookup(host, channel, id, lun);
		if (sdev) {
			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
				"scsi scan: device exists on <%d:%d:%d:%d>\n",
				host->host_no, channel, id, lun));
			if (sdevp)
				*sdevp = sdev;
			if (bflagsp)
				*bflagsp = scsi_get_device_flags(sdev,
								 sdev->vendor,
								 sdev->model);
			/* XXX: bandaid until callers do refcounting */
			scsi_device_put(sdev);
			return SCSI_SCAN_LUN_PRESENT;
		}
	}

	sdev = scsi_alloc_sdev(host, channel, id, lun, hostdata);
	if (!sdev)
		goto out;
	sreq = scsi_allocate_request(sdev, GFP_ATOMIC);
	if (!sreq)
		goto out_free_sdev;
	result = kmalloc(256, GFP_ATOMIC |
			(host->unchecked_isa_dma) ? __GFP_DMA : 0);
	if (!result)
		goto out_free_sreq;

	scsi_probe_lun(sreq, result, &bflags);
	if (sreq->sr_result)
		goto out_free_result;

	/*
	 * result contains valid SCSI INQUIRY data.
	 */
	if ((result[0] >> 5) == 3) {
		/*
		 * For a Peripheral qualifier 3 (011b), the SCSI
		 * spec says: The device server is not capable of
		 * supporting a physical device on this logical
		 * unit.
		 *
		 * For disks, this implies that there is no
		 * logical disk configured at sdev->lun, but there
		 * is a target id responding.
		 */
		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
					"scsi scan: peripheral qualifier of 3,"
					" no device added\n"));
		res = SCSI_SCAN_TARGET_PRESENT;
		goto out_free_result;
	}

	res = scsi_add_lun(sdev, result, &bflags);
	if (res == SCSI_SCAN_LUN_PRESENT) {
		if (bflags & BLIST_KEY) {
			sdev->lockable = 0;
			scsi_unlock_floptical(sreq, result);
		}
		if (bflagsp)
			*bflagsp = bflags;
	}

 out_free_result:
	kfree(result);
 out_free_sreq:
	scsi_release_request(sreq);
 out_free_sdev:
	if (res == SCSI_SCAN_LUN_PRESENT) {
		if (sdevp)
			*sdevp = sdev;
	} else {
		if (sdev->host->hostt->slave_destroy)
			sdev->host->hostt->slave_destroy(sdev);
		if (sdev->host->transportt->cleanup)
			sdev->host->transportt->cleanup(sdev);
		put_device(&sdev->sdev_gendev);
	}
 out:
	return res;
}

/**
 * scsi_sequential_lun_scan - sequentially scan a SCSI target
 * @sdevscan:	scan the host, channel, and id of this Scsi_Device
 * @bflags:	black/white list flag for LUN 0
 * @lun0_res:	result of scanning LUN 0
 *
 * Description:
 *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
 *     scanned) to some maximum lun until a LUN is found with no device
 *     attached. Use the bflags to figure out any oddities.
 *
 *     Modifies sdevscan->lun.
 **/
static void scsi_sequential_lun_scan(struct Scsi_Host *shost, uint channel,
		uint id, int bflags, int lun0_res, int scsi_level, int rescan)
{
	unsigned int sparse_lun, lun, max_dev_lun;

	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
			" host %d channel %d id %d\n", shost->host_no,
			channel, id));

	max_dev_lun = min(max_scsi_luns, shost->max_lun);
	/*
	 * If this device is known to support sparse multiple units,
	 * override the other settings, and scan all of them. Normally,
	 * SCSI-3 devices should be scanned via the REPORT LUNS.
	 */
	if (bflags & BLIST_SPARSELUN) {
		max_dev_lun = shost->max_lun;
		sparse_lun = 1;
	} else
		sparse_lun = 0;

	/*
	 * If not sparse lun and no device attached at LUN 0 do not scan
	 * any further.
	 */
	if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
		return;

	/*
	 * If less than SCSI_1_CSS, and no special lun scaning, stop
	 * scanning; this matches 2.4 behaviour, but could just be a bug
	 * (to continue scanning a SCSI_1_CSS device).
	 *
	 * This test is broken.  We might not have any device on lun0 for
	 * a sparselun device, and if that's the case then how would we
	 * know the real scsi_level, eh?  It might make sense to just not
	 * scan any SCSI_1 device for non-0 luns, but that check would best
	 * go into scsi_alloc_sdev() and just have it return null when asked
	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
	 *
	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
	     == 0))
		return;
	 */
	/*
	 * If this device is known to support multiple units, override
	 * the other settings, and scan all of them.
	 */
	if (bflags & BLIST_FORCELUN)
		max_dev_lun = shost->max_lun;
	/*
	 * REGAL CDC-4X: avoid hang after LUN 4
	 */
	if (bflags & BLIST_MAX5LUN)
		max_dev_lun = min(5U, max_dev_lun);
	/*
	 * Do not scan SCSI-2 or lower device past LUN 7, unless
	 * BLIST_LARGELUN.
	 */
	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
		max_dev_lun = min(8U, max_dev_lun);

	/*
	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
	 * until we reach the max, or no LUN is found and we are not
	 * sparse_lun.
	 */
	for (lun = 1; lun < max_dev_lun; ++lun)
		if ((scsi_probe_and_add_lun(shost, channel, id, lun,
		      NULL, NULL, rescan, NULL) != SCSI_SCAN_LUN_PRESENT) &&
		    !sparse_lun)
			return;
}

/**
 * scsilun_to_int: convert a scsi_lun to an int
 * @scsilun:	struct scsi_lun to be converted.
 *
 * Description:
 *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
 *     integer, and return the result. The caller must check for
 *     truncation before using this function.
 *
 * Notes:
 *     The struct scsi_lun is assumed to be four levels, with each level
 *     effectively containing a SCSI byte-ordered (big endian) short; the
 *     addressing bits of each level are ignored (the highest two bits).
 *     For a description of the LUN format, post SCSI-3 see the SCSI
 *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
 *
 *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
 *     the integer: 0x0b030a04
 **/